Powder feed hopper for capsule-forming machine



United States Patent Inventor Maharaj Krishen Mehta Lakeside, Cardiff,Wales Mar. 10, 1969 Dec. 22, 1970 P. Leiner & Sons (Encapsulations)Limited Treforest, Glamorganshire, Wales Appl. No. Filed PatentedAssignee POWDER FEED HOPPER FOR CAPSULE- FORMING MACHINE 5 Claims, 3Drawing Figs.

U.S. Cl 222/226,

Int. Cl. F0lf 11 00, F014 13/00 Field of Search 222/226,

25 l 252. 505(T), 510: 259/2(T), 28(T) [56] References Cited UNITEDSTATES PATENTS 2,798,645 7/1957 Keen et al 222/226 2,801,774 8/1957l-larkess et al. 222/226 Primary Examiner-George T. HallAttorney-Woodhams, Blanchard and Flynn PATENIEDUEEZZISYU 3,549,056 sum 2OF 2 Fig.2.

MMWQM POWDER FEED HOPPER FOR CAPSULE-FORMING MACHINE The presentinvention relates to machines for encapsulation of powders.

Various types of machine having been proposed and are in use for themanufacture of filled gelatin capsules containing material in powder orgranular form. For example, British Patent Specification No. 881,022describes apparatus in which capsules are formed by bringing togethercapsule halves formed in two strips of gelatin or the like which passround two revolving die rolls having matching die pockets in theirsurface to which suction is applied to form the capsule halves. Thecapsule halves formed on each die roll are filled with the aid of a feedroll mounted directly above the die roll and having charge chambers inits periphery which are filled with powder from a hopper and from whichthe powder is ejected into the formed capsule halves. The formed andfilled capsule halves are brought into juxtaposition and aresuccessively cut out by pressure and sealed together to form capsules.

Various types of feed rolls and hopper combinations, other than that inPat Specification No. 881,022 have been proposed for filling the formedcapsule halves, e.g. British Patent Specifications Nos. 1,109,407 and1,118,520 describe such apparatus.

However, in all such machines, the capacity of the hopper on the feedroll is limited and the hopper has to be replenished frequently.

In accordance with the present invention there is provided a powder feedsystem for an encapsulating machine including a delivery hopper closedat its lower side by a feed roll having charge chambers in its-surfacefor the reception of charges of powder from the delivery hopper,characterized by a main hopper mounted above the delivery hopper andhaving one or more flexible pipes descending into the delivery hopper,means being provided for moving the lower ends of the pipes to and frowithin the delivery hopper.

In this apparatus the powder in the delivery hopper closes the lowerends of the pipes and thereby terminates the supply when the powderrises above a certain level while the movement of the pipes ensures afree flow when the level in the delivery hopper falls and uncovers theends of the pipes.

In any automatic method of filling the feed roll hopper from a mainhopper, it has to be ensured that the flow or feed of powder iscontinuous and that the feed roll hopper is neither starved noroverfilled. It has been found, from experience, that the simplest way ofaccomplishing this is to mount a main hopper of a standard designapproximately 1 foot above the feed roll hoppers and lower threeflexible plastic tubes of k inch --1 inch bore from the bottom of themain hopper into the feed roll hoppers, so that each tube is heldbetween two scrapers or wiper arms described in Specification No.1,118,520 and ends approximately inch 1 inch above the surface of theend roll. With this arrangement, the scrapers will move the tube ends toand fro to assist their emptying action and the gap of inch -1 inch willprevent overfilling the feed roll hopper. In connection withoverfilling, it is found that after the level of powder being emptiedthrough the tubes reaches the lower end of the tube the powder will staywithin the tube and will not flow out.

The main hopper can be of any standard design such as the vibratingtype. It may also be of the type used in filling twopiece hard capsules,where a rotating arm in the bottom of a circular hopper is continuouslypushing material down a tube connected to the bottom of the hopper.Generally, in hard capsule filling machines, in such an arrangement anelectronic device is used to stop the rotating arm when enough powder isreceived in the filling machine. In the arrangement proposed, the armrotates continuously and the level in the feed roll hopper is maintainedby the gap provided between the end of the feeding tubes and the feedroll.

The invention will be described in more detail with the aid of examplesillustrated in the accompanying drawings, in which:

FIG. 1 is a view in section through the feed roll hopper of one form ofpowder feed system in accordance with the invention,

FIG. 2 is a similar view of an alternative powder feed system inaccordance with the invention, and

FIG. 3 is a partial end view of the system of FIG. 2.

The system shown in FIG. 1 comprises a feed roll hopper 1 containing ascraper frame 2 which, as described in the abovementioned SpecificationNo. 1,1 18,520, is vibrated by a cam 3 in the form of a rotatingskew-mounted disc in order to move scraper blades 4 to and fro acrossthe periphery of a feed roll 5. The delivery hopper 1 is fed from a mainhopper 6 by flexible feed tubes 7 delivering the powder 8 into thedelivery hopper. The lower end of each 'feed tube 7 is located betweenpegs 9 on the oscillating frame 2 so that it is moved to and fro withthe scraper blades.

In the system shown in FIGS. 2 and 3 the scraper blades are omitted andthe lower ends of the flexible pipes 7 are sufficiently close to thefeed roll 5 to assist in sweeping the powder 8 into charge chambers 9Ain the feed roll. For this purpose the pipes 7 are aligned approximatelywith the rows of charge chambers 9A extending around the feed roll.

The pipes 7 are connected to the main hopper 6 through a rotary shutoffvalve 10 having a valve body 11 rotatable by a lever 12 to preventpassage of powder from the main hopper to the delivery pipes.

The pipes 7 pass through closely fitting apertures in a transparentcover plate 13 of synthetic plastics material which covers the top ofthe feed roll hopper 1. The cover plate 13 has a metal frame 14 fromwhich extends a lug 15 which engages in a cam groove 16 in a rotary cam17. The cover plate 13 and with it the pipes 7 are thereby reciprocated,the cover plate being guided by brackets 18 engaging the frame 14.

I claim:

1. In an encapsulating machine a powder feed system comprising adelivery hopper, a feed roll closing the lower side of the deliveryhopper and having charge chambers in its surface for the reception ofcharges of powder from the delivery hopper, a main hopper mounted abovethe delivery hopper, at least one flexible'pipe descending from the mainhopper into the delivery hopper and means for moving the lower end ofsaid pipe to and fro within the delivery hopper.

2. In a machine as claimed in claim 1 a scraper frame, a plurality ofscrapers carried by said scraper frame, and means for reciprocating thescraper frame to move the scrapers over the feed roll, said pipe havingits lower end engaged by said scraper frame for to-and-fro movement ofthe pipe.

3. In a machine as claimed in claim 2 the means for reciprocating thescraper frame comprising a cam.

4. In a machine as claimed in claim 1 a cover for said delivery hopper,openings in said cover for the passage of said pipes, and means forreciprocating the cover to effect to-andfro movement of the pipes.

5. In a machine as claimed in claim 4, grooves guiding said cover, a lugon the said cover, and a rotary cam having groove engaged by said lug toreciprocate the cover.

